The Mobile Radiological Intervention Unit (CMIR) in France
By Col. Denis Giordan, Deputy Director of the Savoie Fire Department, France
The radiological units, created in 1980, are teams of 7 firemen able to cope with and overcome an incident or an accident of a radioactive nature. A CMIR is composed of two teams. The first one, the assessment team includes two or three firemen. Their missions include the assessment and research, the marking of the radiant and contaminated zones, the evacuation of people standing in the danger area and the intervention team support and assistance. The second team is the intervention team. It has the same abilities as the assessment team, but the job of these two or three firemen is slightly different. They are specifically in charge of setting up the contamination inspection point, where the contamination of people and rescue teams is controlled. They also search for sealed sources and for contamination on the ground and in the air in the « soiled zone » and cover the sealed sources and radioactive waste. Finally, they inspect persons in order to find contamination and take samples. Many CMIR, in France, have made the choice of having two or three intervention teams and no assessment team, in order to be more efficient.
The « radioactivity engine » has numerous equipment, in particular radioactivity detectors organized in boxes, adapted for each specific task within the assignments of the CMIR. Some examples of tasks are the marking out of the radiant zones and search for sealed sources, the marking out of contaminated areas and search for contamination in the « soiled zone », the contamination inspection of persons, etc.
Radiation detectors measure dose and dose rate or counts per second. Each group of two men uses either one of the following: an ictometer (counts per second) to find sealed sources or contamination, or a ratemeter (dose rate and dose) to warrant security of these two men.
Last, but not least, the CMIR work with anti-contamination protection uniforms that are made up of 2 layers. The protection mask is used as a filter or a breathing apparatus. Numerous bottles, filters, pliers and test tubes allow taking samples which are analysed at the laboratory. Lead boxes and lead shields ensure the seclusion of the radiant sources. Polyethylene rolls and bags can be used to contain contamination and to cover the soiled material. The CMIR is also equipped with marking material.
Over the last ten years, we include some main innovations in our equipment.
The first ones are individual electronic dosimeters, reachable by radio to ensure a regular follow-up of the dose amount for each team member. This kind of dosimetry is necessary if the ALARA principle « As low as reasonably achievable » is to be respected, a compulsory directive in European laws. The two other radioprotection principles are the justification of radiation exposure and the respect of dose limits.
Additionally, we saw the greater use of mobile spectrometers allowing the identification of the radioactive elements. By comparing the radiation energy using a radioelements reference list, we allow the identification of nuclear elements. The identification is very important to understand the origin of a radioactive incident.
The use of radiation detector linked to a G.P.S. system has become more common. This system enables the automatic mapping of the dose rate, therefore allowing a rapid response to a nuclear disaster.
Finally, we deployed, few years ago, new detection gates for the inspection of contaminated people. Indeed, on the side of thorough decontamination, the biggest problem is always to have too much “potential contaminated persons” and not enough decontamination means immediately available. It should be possible to limit the flow of victims to decontaminate by discrimination between “just involved” and “actually contaminated”. In the past, only handled detectors was used in all situations, in front of all type of radionuclide (detection gates or portals existed but with plastic scintillators and could only detect photons above 50 keV). On the other side, have you ever tried, while donning protection clothing, to control fifty or a hundred persons? After a while, you become less effective. Thus, the new gate is able to detect gamma rays, soft betas and weak energy photons (indirectly, alpha and beta particles), by having a “whole body classic gates” (with large volume plastic scintillators) and “face, hands and feet” additional probes (X-ray and GM pancake). Head, hands and feet are the places that are the most easily contaminated.
Dispelling the doubt
What are the criteria for selecting radioactive contamination detectors? It is necessary to consider at least three parameters: the types of radiation, the radiation energies and the detection conditions (humidity, temperature, etc.). In a doubtful situation, when neither the radioelement, nor the radiations are known, French fire-fighters use two different probes. The first probe is the X-ray probe with a thin iodize sodium and a beryllium window. It measures, with a good output, photons of an energy ranging between 5 and 80 keV. It also detects high energy gammas, directly due to the measurement of their Compton photons, and alphas and energetic betas, indirectly, at the time of the rearrangement of the electronic procession. It is important to note that, in the case of an alpha probe, you will not be able to detect the alpha if there is humidity (after rain or decontamination). The X-ray probe allows this detection. However, it does not detect weak energy betas. Thus, it is necessary to have a second probe: the GM pancake probe with a Mylar window, which is effective for the latter, at an energy of 30 keV. It detects too, but with small efficiency, alphas, photons and high-energy betas.
Why two probes? Some experts are convinced that a single detector is able to detect all type of radiations with good efficiency, at various energies, in variable weather conditions. However, universal detector does not exist, whereas the two probes approach is efficient in almost all situations. They are complementary and, together, allow to dispel the doubts.
If the radioelement, the radiation types and the energy is known, adapted detectors may be used: thick sodium iodide crystal for gamma of an energy higher than 30 keV, plastic scintillator for beta particles of an energy higher than 50 to 150 keV and depending on its thickness, gamma rays of an energy higher than 30 keV, zinc sulphide scintillator for alphas, helium 3 for neutrons etc.
Knowledge and ability
Teams can only be efficient with specific and defined competencies. Therefore, each fireman, at the beginning of his career, learns how to protect the population and himself from radioactive hazards. This includes to be able to recognize the danger of sealed sources, the danger of radioactive contamination, the use of radioactive materials in industry, medicine, research, transport, or energy. They also learn how to protect themselves from the radiation effect, how to properly use protective clothing, or how to evacuate people standing in the danger area for instance.
According to the level of responsibility, there are 4 levels of competencies: the assessment team members, the intervention team members, the chief of a CMIR and the head of several CMIR The number of specialists is small. Out of two thousand and five hundred firemen in the county of Yvelines, only about 50 possess the required competencies to participate in a radioactive rescue operation.
Different training courses are available in France to reach the different levels. The « Rad 1 course » is the first level. In about forty hours, firemen learn the job of assessment team. The « Rad 2 course » is the second level: it enables firemen to reach the level of an intervention team member in about forty hours. Only the members of assessment team are authorized to take it. The « Rad 3 Courses » is the third level that is organized for the CMIR chiefs. The chiefs of several CMIR are called Technical Advisers. They learn their job over two weeks in the « Rad 4 course ». Only the CMIR chiefs are admitted.
Each fire department in France with a CMIR is authorized to organize Rad 1 and 2. Seven fire departments in France organize « Rad 3 ». The students come from the county of the same area. Only the French National Fire Officer School can organize the « Rad 4 » for students coming from all over the country. There are ten to twelve firemen per training course. The French Home Office publish a National Recommendation Guide for each level, following the fire departments’ recommendations.
Experience is essential for these small teams and is shared in these trainings. Exams, training and use of detectors are made with real sources and contamination. Only a few firemen from each county are authorized to use and transport radiological elements. It’s important to understand that each specialist is not a physician or an academic. We choose to teach radiological rescue to « regular firemen » who are used to dealing with complicated situations and who are used to making choices in an uncertain environment. Everyday they extinguish fires, ensure first aid in ambulances or assist at the scenes of road accidents. However, when there is a radiological problem, the fire department calls them.
The decontamination of persons has two objectives: to prevent the internalization of the contamination (which often occurs quickly), to avoid the transfer of contamination to other persons, objects or places. It may be necessary in case of technological accident and / or C.B.R.N. malicious act.
Since 2001, emergency departments have been highly involved in mass decontamination. Rescue services in France have been equipped with population protection equipment to deal with a major accident or malicious act of a technological nature. The most important equipment are decontamination units, under tents or in shelter. They are expensive but allow treating a few tens of able-bodied and invalids per hour.
These means are part of an adaptive response capacity based on the nature of the contaminant, number of people involved, meteorology, resources of the intervention area, increase in powers of the emergency means, need of bio safety after use, etc. Through experiences, many unknowns were dispelled, the equipment was adapted to new operational concepts and made available in a "toolbox" ready to use. This new doctrine was built in opposition to the monolithic doctrine professed by certainty-makers in the beginning of the CBRN threats in 1995/2005.
Several operational gaps yet remained: 1 – Quantitative aspect: if the “industrial” decontamination units were to be used in large quantity, how to reconstitute and guarantee a coherent coverage on the whole French territory, immediately and easily? (Manufacturers will not be able to produce the necessary decontamination units within a few days to reconstitute the initial capacity). 2 - Qualitative aspect: when reinforcement teams are sent abroad, weights and volumes are measured. How can a decontamination capacity be created upon arrival? (There is no concept to guarantee decontamination in good conditions). 3 - Financial aspect: face to a small number of contaminated people, what are the options? Should we call a decontamination unit which costs more than 100,000€? (There is no “low cost” solution for decontamination).
These questions were resolved thanks to the “hand-made disposable” decontamination showers. Our concept permits easy access to shower components, easy installation, adaptability according to operational constraints, possible integration in a tent or in a building structure (gymnasium, swimming pool, etc.). Some experiments, with various radionuclides, confirmed its effectiveness. Thus, in addition or instead of “factory built” decontamination units, it is now possible to deploy one or more showers in order to take care of a small or large number of contaminated people.
The fact that these assignments are guaranteed by firefigthers allows any point of the national territory to be reached rapidly. There are about 50 CMIR in France. They participate in about 200 interventions a year as one or several units. About 40% of the intervention concerns detection of an ownerless radioactive source. 7% concerns fire and explosion in the presence of radioactive source. 7% is linked to the carriage of radioactive materials and 9% concerns the carriage of radioactive materials control. 5% of the interventions are linked to lightning conductors and 21% are false alarm without radioactivity. In my county, in Savoie, we usually have about fifteen radiological operations per year. Experience is very important for these small teams. Some firemen have been members of my CMIR for ten years and have participated in more than eighty radioactive operations. Among emergency partners, there are not a lot who have such experience.
The organisation is the same for chemical and biological rescue operations.
Colonel Denis Giordan works for the Savoie Fire Department in France. He serves as a Fire officer since 33 years. Today, he is also Deputy Director of the Savoie Fire Department that represents 460 professionals, 1 800 volunteers, 35 000 operations per year, and 61 million euros of budget per year. As part of his duties, he is also a Nuclear and Radiological technical advisor. Formerly, he has been “zonal R.N. technical advisor” at the French Paris Civil Defence Zone and at the East Civil Defence Zone. He is also the Head of “radioprotection and R.N. risks and threats” teachers' team at the French national fire officers school. During his years of service, he also wrote numerous papers on technological risks and CBRNE threats. He especially co-wrote the French reference book: “C.B.R.N.E. terrorism”. Col. Giordan is a member of the CBRN commission of the French national fire fighters federation and the french representative within the Hazmat commission of the CTIF, the International Association of Fire and Rescue Services. Finally, he also teaches at the Upper Alsace University for both the “CBRN risks and threats” specialised Master degree and the “CBRN risks and threats” University diploma).